Field of the Invention
The present invention relates to a method for producing a profile and to a manufacturing system for producing a profile.
Description of Related Art
In the vehicle industry, use is increasingly made of press-hardened components composed of manganese-boron steels having tensile strengths of at least 1500 MPa. A large portion of said components is configured as a shell component. Shell components are typically designed with respect to the geometry thereof in such a manner that, after the production thereof, said shell components do not have a closed cross section. Only after two or more shell components are connected can said structure have a closed profile. However, structural measures are required in order to join the shell components. These include, for example, component flanges which can raise the entire weight of the finished profile. In addition, it is possible, for example during resistance spot welding, for the connection of the individual components to be present only locally and to be associated with an additional application of heat.
Precisely in the case of press-hardened components, a locally acting, retrospective heat treatment, for example in the course of resistance spot welding or soldering, may result in a metallurgical notch and may have a negative effect on the component function of the shaped part.
It is possible for downstream process steps to be reduced by the use of hollow profiles which, for the most part, already have the final constructional geometry thereof before the press-hardening. These profiles include, for example, rolling profiles or profiles produced by means of U and O bending processes. After the deformation, said profiles can be closed as a profile, for example, by means of laser beam welding. Subsequently, the final component properties are then produced by means of the shape hardening. For this purpose, the material, preferably a manganese-boron steel, is heated above the hardening temperature, in particular above Ac3, and subsequently hardened by cooling.
However, because of the heating process required for the hardening, thermal stressing of the components or material surface, in particular scaling or partial decarburization, takes place here. Since scaling has an adverse effect on the adhesion of paint, the hardened materials have to be cleaned at a cost here. At the same time, when coated material is used, flaking off of the coating may occur during cold deformation, as a result of which the adhesion of paint is also adversely affected in this case.